In conventional incubators for analyzers, evaporation covers are provided to hold test elements at the stations of the incubator. Such covers are spring-biased downwardly, to allow the test elements to be inserted and removed against the bias of the spring.
Although this arrangement has worked satisfactorily, there have been some disadvantages with the springs heretofore provided. In some cases, the springs comprise a simple one-leg leaf element screwed into place to bias the cover downwardly. Such springs are not readily removable, for example, in case of a jam or if cleaning is needed. In other cases, removable leaf springs have been provided, but such springs have been fairly complicated in shape. For example, as shown in commonly-owned U.S. application Ser. No. 346,205 filed on May 2, 1989 and entitled "Universal Evaporation Cover", now U.S. Pat. No. 4,963,333, there is disclosed a spring having three legs projecting from a body. Although such a spring works satisfactorily in most instances, it has a disadvantage in that its shape is more complicated, and thus more difficult to manufacture and assemble. Furthermore, its design features an aperture in the longest of the three legs to retain the evaporation cover with respect to the spring. Such an aperture necessarily involves a sloppy fit, that tends to render uncertain the exact location of the cover in the station of the incubator. For best operation of the cover, it is preferred that the cover always be fully withdrawn into the station of the incubator. This did not always occur using such an aperture.
Therefore, there has been a need prior to this invention to provide a spring for covers in an incubator that avoids the above-noted disadvantages.